<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style type="text/css">
			*{
				margin: 0;
				padding: 0;
			}
			html,
			body{
				width: 100%;
				height: 100%;
				overflow: hidden;
			}
			.wrap{
				width: 300px;
				height: 300px;
				position: absolute;
				top: 0px;
				right: 0px;
				bottom: 0px;
				left: 0px;
				margin: auto;
				transition: 2s;
			}
			.wrap > div{
				margin: 10px;
				width: 130px;
				height: 130px;
				border: 1px solid;
				background-color: pink;
				float: left;
				box-sizing: border-box;
			}
			.wrap > div:nth-child(1),
			.wrap > div:nth-child(4){
				border-radius: 0px 50%;
			}
			.wrap > div:nth-child(2),
			.wrap > div:nth-child(3){
				border-radius: 50% 0px;
			}
			.wrap:hover{
				transform: rotate(120deg);
			}
		</style>
	</head>
	<body>
		<div class="wrap">
			<div></div>
			<div></div>
			<div></div>
			<div></div>
		</div>
	</body>
</html>
